With the development of thin-film transistor liquid crystal display (TFT-LCD) technology and the advance in industrial technology, the production cost of liquid crystal display (LCD) devices is reduced and the manufacturing process is gradually improved. TFT-LCDs have become the mainstream technology in the flat-panel display field instead of cathode ray tube (CRT) display, and have become ideal display devices in the market and the hearts of consumers due to the advantages of the TFT-LCDs.